The purpose of this Guidance Note is to help countries to assess the quality of public spending on science, technology, and innovation (STI). It adopts a results-oriented framework, combining the consolidation of STI expenditures with the analysis of their main outputs, intermediate outcomes, and developmental impact. The framework proposes the analysis of three main sources of deficiencies: (i) program design/implementation; (ii) institutional conditions; and the (iii) composition and level of public expenditure.